Limbaugh blasted the pontiff on Wednesday, a day after Francis released "Evangelii Gaudium" (The Joy of the Gospel), a 50,000-word statement that calls for church reform and castigates elements of modern capitalism.

The Vatican issued the English translation of "Evangelii," which is known officially as an apostolic exhortation and unofficially as a pep talk to the worlds 1.5 billion Catholics.

Francis - the first pope ever to hail from Latin America, where he worked on behalf of the poor in his native Argentina - warned in "Evangelii" that the "idolatry of money" would lead to a "new tyranny."

The Pope also blasted "trickle-down economics," saying the theory "expresses a crude and naïve trust in the goodness of those wielding economic power."

The Pope's critique of capitalism thrilled many liberal Catholics, who have long called on church leaders to spend more time and energy on protecting the poor from economic inequalities.

But Limbaugh, whose program is estimated to reach 15 million listeners, called the Pope's comments "sad" and "unbelievable."

"It's sad because this pope makes it very clear he doesn't know what he's talking about when it comes to capitalism and socialism and so forth."

In fact, Argentina was a battlefield between leftist socialists and right-wing security forces during much of Francis' early career in the country, where he was a Jesuit priest and later archbishop of Buenos Aires.

Limbaugh, who is not Catholic, said he admires the faith "profoundly." He admired Pope Francis as well, "up until this," Limbaugh said.

The talk show host also said that he has made numerous visits to the Vatican, which he said "wouldn't exist without tons of money."

"But regardless, what this is, somebody has either written this for him or gotten to him," Limbaugh added. "This is just pure Marxism coming out of the mouth of the Pope."

Limbaugh took particular issue with the Pope's criticism of the "culture of prosperity," which the pontiff called a "mere spectacle" for the many people who can't afford to participate.

"This is almost a statement about who should control financial markets," Limbaugh said. "He says that the global economy needs government control."

"I'm not Catholic, but I know enough to know that this would have been unthinkable for a pope to believe or say just a few years ago," Limbaugh continued.

In fact, Francis' predecessor, Benedict XVI, now pope emeritus, could be just as strong a critic of capitalism.

In 2009, Benedict, in an official church document called an encyclical, said there was an urgent need for "a political, juridical and economic order" that would "manage the global economy."

As Limbaugh notes, Benedict's predecessor, the late Pope John Paul II, was a noted foe of communism, after living under its oppressions in his native Poland. But even John Paul thought that unregulated capitalism could have negative consequences.

In "Evangelii," Francis called for more of a spiritual and ethical revolution than a regulatory one.

"I encourage financial experts and political leaders to ponder the words of one of the sages of antiquity: `Not to share one’s wealth with the poor is to steal from them and to take away their livelihood. It is not our own goods which we hold, but theirs,'" said Francis, quoting the fifth-century St. John Chrysostom.

Liberal Catholics defended Pope Francis on Monday, calling on Limbaugh to apologize and retract his remarks.

"To call the Holy Father a proponent 'pure Marxism' is both mean-spirited and naive," said Christopher Hale of the Washington-based Catholics in Alliance for the Common Good. "Francis's critique of unrestrained capitalism is in line with the Church's social teaching."

Limbaugh is not the only conservative commentator to take issue with the Pope's views on capitalism.

“I go to church to save my soul," said Fox News' Stuart Varney, who is an Episcopalian. "It’s got nothing to do with my vote. Pope Francis has linked the two. He has offered direct criticism of a specific political system. He has characterized negatively that system. I think he wants to influence my politics.”

It doesn't sound like the criticism is slowing Francis down, however. He's started sending a Vatican contingent, including the Papal Swiss Guards, into Rome to deliver food and charity.

The CNN Belief Blog covers the faith angles of the day's biggest stories, from breaking news to politics to entertainment, fostering a global conversation about the role of religion and belief in readers' lives. It's edited by CNN's Daniel Burke with contributions from Eric Marrapodi and CNN's worldwide news gathering team.